Monday, November 24, 2008

Explosion+Son

I've been biting my tongue for the past while on the H+Son rims that are currently conveying along in the big old internet hype machine. I have some theories on these rims, and how they made it to market so fast. ..but for now, I'll let the picture tell the story.



This is the first reported case of failure I've seen. [Full Set here] The rim is 12mm deeper than a Velocity Deep V, and weighs less. The material had to go somewhere. (in this case, it went outwards) I've felt these rims and how thin the aluminum extrusion is. Clearly a redesign is in order.. but just how many of this first revision have made it to market?

NEXT DAY EDIT [in square brackets]:
I'm going to come out and say it.

I think they are made by the Giant Global Group, and intentionally branded as a startup 'boutique' brand to avoid the stigma associated with the Giant brand in North America.

[[THIS THEORY IS WRONG. SEE COMMENT FROM TZUSING]]

H+Son has two products that came to market VERY fast without any internet mention. The Formation Face and SL42 rims.



tarkbike.com user Tzusing (is the Son in H+Son) says:

"My company's background is def more in raw material and production techniques...(meaning i come from a background of all those factories that make bicycle parts for brand names)"
"HKfixed is indeed selling my rims. But ordering from me is direct from the Kun Shan factory in China. (1 hour west of shanghai) and not Hong Kong."


Giant Light metal appears to be the main bicycle rim manufacturer in Kunshan... and the Giant Bowery '84 also has what appears to be[a 42mm deep rim with a similar extrusion to] the SL42 rim in a lower spoke count.

8 comments:

kale said...

I want some papier-mâché rims!

gabrielamadeus said...

Wowza! I had some MTB Salsa Delgado rims fail the same way, although not as epically.

http://farm4.static.flickr.com/3002/3057218306_9fdaff008e_o.jpg

http://farm4.static.flickr.com/3151/3057218132_f274dd180f_o.jpg

The outward pressure from the bead is apparently one of the strongest forces on a rim - who knew!

Tzusing said...

I am not owned by the Giant group.

morgman said...

Wanna hook us up with a couple of rims for testing purposes? I think I'd like a Formation Face, in 32h any colour. Based on that blowout, I might not want to run one on the front, but I'd thrash a rear for fun. What's the maximum recommended pressure?

Tzusing said...

This rim actually took 1 and 1/2 years to develop. And if you can see the rim ripped apart at the tire well, which is the same thickness as a normal road rim.
The tire well is 0.8mm plus or minus 0.1mm
The only part of the rim that's thinner than a normal road rim is the sidewall, which is not where the rim tore.

((lyledriver)) said...

Thanks for the clarification Tzusing. (on both your company, and the tire well thickness) There is a lot of misinformation out there. I appreciate the fact that you are going around doing damage control. This shit spreads like wildfire.

Things like:

"I imagine the heat from skidding probably increased the pressure past the rim's limit."

"From my point of view it looks as if maybe tricking and other bs worked to create a stress riser by pushing the valve stem against the hole. once you have a stress riser in something full of stress like a wheel, all it takes is one false move and your shit is over."

"THESE RIMS COULD BE MADE OUT OF DIAMONDS AND NEGATIVE GRAMS AND I WOULD STILL HATE THEM SO HARD"

Obviously those aren't the most intelligent comments, but as long as you can keep that crowd at bay, you'll be golden.

Any word on how many have shipped so far?

((lyledriver)) said...

Also, what PSI would you rate your rims at with a 19mm tire?

For reference a Mavic Open Pro states 146psi MAX. Obviously there is a healthy margin of safety there.

I'm curious because you have mentioned doing QC at the factory, so I am under the impression that these rims have undergone various stress tests before being shipped out.

If these rims are to be used for 'going fast' as you put it, on a steep velodrome, they will be exposed to forces much higher than regular road riding. ..and the lack of brake surface indicates that you are intending them for track bike use.

Thank you stopping by=]

Tzusing said...

lyle,
Besides the many standard testing of rims, including the European CN tests, the SL Rims have been tested by professional roadies.
I admit the formation face rims have not been tested by track riders, but they are built on the sl42 and all sides of the rim are thicker than the sl42 except for the upper leg. (which you can see is not where the breakage occurred)

We have tested our rims by over inflating an inner tube with a wire bead tire. This was actually to test the strength of the upper leg and not the tire well.
The rim was not damaged in most cases. The worst case we saw was a bent upper leg.